Luminous golf practice device

ABSTRACT

A device designed to be fitted to or built into a golf club such as a putter to assist in learning the correct club position, in particular for indoor or home putting practice. A transmitter unit is releasably attached to the shaft of the club and comprises a laser diode for transmitting a parallel light beam towards an optical unit having a cylindrical lens above the club iron. The lens diffuses the light along a vertical plane to form a beam directed at the ground in front of the iron, whereby the player is able to see a line of light on the ball and on the ground indicating the direction in which the ball will travel depending on the position of the striking surface of the iron. In one embodiment, the optical system may be supported by an arm attached to the shaft.

The object of the present invention is an auxiliary luminous device forgolf practice, especially for practicing strokes or putting, consistingof a light source and an optical unit designed to diffuse a light beamonto a plane, said transmitter and said optical unit being attached to agolf club in such a way that the plane over which the light is diffusedis perpendicular to a striking surface on the club and forms a line oflight on the ground.

BACKGROUND OF THE INVENTION

Given the increasing popularity of golf and the lack of availablecourses, golfers tend to practice with specialized equipment which canbe used in a yard or other available space. Various types of simulatorshave been proposed for the purpose of swing practice, that is,forcefully hitting the ball forward. However, rolling the ball orputting practice require only a flat surface covered with suitablecarpeting and with a hole or substitute goal. In putting the ball is hitwith a club called a putter, with a relatively broad iron whose strikingsurface is nearly vertical when contacting the ball. The main difficultyin putting is to orient the striking surface of the iron along a planewhich is perpendicular to the vertical plane passing through the centerof the ball and the through center of the hole. In reality, a golfer canonly acquire the habit of orienting the club correctly after numerousrepetitive practice strokes, since the direction which the ball takessupplies the only indication of whether the iron position was correct.

Putting practice devices are already known and consist of one or twoluminous diodes on the putter head, each emitting a linear beam in adirection perpendicular to the striking surface, thereby allowing thegolfer to stop the club in the ideal position. However, such a device isof little use when the club moves, as the line of each light beam on theground is a point which moves too quickly to be of any use to the playerin correcting his or her motions.

U.S. Pat. No. 3,953,034 concern an auxiliary device mounted on a golfclub for swing practice. A linear laser light beam emitted by a lightsource attached to the handle strikes a convex mirror attached below thehandle near the striking surface. The laser beam is reflected forward inthe form of a planar vertical beam perpendicular to the strikingsurface, creating a line of light on the ground which predicts thedirection parallel to the probable trajectory of the ball. In actuality,such a device allows one to verify only the horizontal orientation ofthe striking surface and no other parameters relating to its position,notably the possibility that it will diverge laterally from the ball.Furthermore, it is not useful for putting practice when the ball isfairly close to the hole, since the light beam it creates would passbeside the hole and would not give the golfer a clear, preciseindication.

SUMMARY OF THE INVENTION

The object of the present invention is to improve devices such as thosedescribed above and make them useful for putting practice by allowingthe user to visualize the ideal club position more clearly at the momentthe club strikes the ball.

To accomplish, the device of the invention is characterized in that theplane over which the light beam is diffused passes through one pointwhere the ball impacts the striking surface, and in that the opticalunit is located behind a plane defined by the striking surface.

This arrangement allows the golfer to place the putter exactly acrossfrom the ball and at the same time, to orient it correctly, thanks tothe line which the light beam traces simultaneously upon the ball and onthe ground. Furthermore, all these indications are present both when theclub is stationary and when it is moving. The optical unit mayadvantageously be located higher than the striking surface, so that onepart of the diffused beam always passes above the ball.

The light beam is preferably a beam parallel to the output of thetransmitter, which may be a laser transmitter, and the optical unitcomprises a cylindrical lens. The device may have a source of electricalenergy supplying the transmitter and attached to the golf club.

In one particular embodiment, the optical unit is built into thetransmitter which is attached to an adjustable arm that can be detachedfrom the shaft of the golf club.

In another embodiment, the optical unit has a reflector which isintegral with the cylindrical lens and is situated at some distance fromthe transmitter. In this case the transmitter may be located on the clubshaft or it may be incorporated into the shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention and its advantages will be more apparent from thefollowing-description of two embodiments, with reference to the attacheddrawings, wherein:

FIG. 1 is a perspective of a golf putting club equipped with a devicewhich is the first embodiment of the invention;

FIG. 2 is a view analogous to FIG. 1 of a second embodiment of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a "putter" golf club 1 for hitting a golf ball 2 and makingit roll across the ground 3 to a hole 4. In known manner, the club 1comprises a shaft 5 with a grip 8 and is attached, at its lowerextremity, to a specially designed club 7 which has a generally flatstriking surface 8 opposite ball 2, and which is normally vertical whenit strikes the ball if the golfer is holding the club properly. An indexmark 9 is notched into the club 7 to indicate the center of the strikingsurface 8, that is, the ideal point of impact 10 between surface 8 andball 2.

In FIG. 1 striking surface 8 is vertical; it is represented by path Y onthe ground and by vertical axis Z passing through point 10. A third axisX orthogonal to axes Y and Z represents the normal straight line onsurface 8 at the point of intersection of axes Y and Z. In the idealposition shown here, axis X follows the ground 8, then surface 8 isvertical, and plane XZ passes through the center of ball 2 and throughthe center of hole 4 since that is the direction in which one wishes toroll ball 2.

The device according to the invention is detachable from club 1. Itconsists of an electronic optical unit 11, a support 12 which can bedetached from shaft 5 and which maintains the adjustable position ofunit 11, a source unit 13 attached to shaft 5 with straps 14, and a pairof electrical conductors 15 connecting units 11 and 13. Unit 11 containsa coherent red light beam transmitter consisting of a laser diode 16emitting in a band of 670 nm. Unit 11 also contains the electroniccircuitry controlling the diode functions.. Laser diode 16 emits aparallel light beam which strikes a cylindrical lens 17 with an axisparallel to axis Y, i.e., the lens disperses the parallel light beaminto a divergent planar beam 18 onto a vertical plane parallel to planeXZ. In effect, because of adjustable support 12, unit 11 is designed sothat beam 18 is located precisely in plane XZ and is directed downwardand in front of club 7. As a result, beam 18 will form a rectilinearline 19 on the ground 3 which, in the position shown, coincides withaxis X. Generally speaking, line led represents the intersection ofvertical plane XZ with the ground 3 and thus shows the golfer thetheoretical trajectory of ball 2 as a function of the orientation ofstriking surface 8 if the ground is perfectly horizontal.

Note that support 12 is attached to shaft 5 by a clip 21 with a wing nut22 or with a pressure or socket device so it can easily be affixed inthe desired position on any type of golf club. This allows the samedevice to be used with various types of clubs. Furthermore, the level ofsupport 12 along sleeve 5 can be changed at will, for example in orderto modify the angle or the range of light beam 18. Source unit 13 mightalso be incorporated within unit 11 or attached to support 12.

In the embodiment shown in FIG. 2 the device comprises a lighttransmitting unit 24 which is attached to shaft 5 of club 1 with straps23 and emits a coherent, parallel light beam 25 toward an optical unit28 held by support 27 attached to club 7. The transmitter 24 contains alaser diode 28, an energy source such as a battery 29 and electroniccircuitry controlling the laser diode. Optical unit 28 is in the form ofa small case with a window 30 at the top, having a cylindrical lens 31and an internal reflector (not shown) designed to reflect the parallellight beam 25 on plane XZ toward cylindrical lens 30. The latter isarranged in the same way as in the preceding example and forms thedivergent light beam 18 so it is directed downward on vertical plane XZ.The advantage of this design over that of the preceding example is thatit concentrates the majority of the weight of the device in the shaft.The angle of parallel beam. 25 in relation to shaft 5 can remainconstant. Beam 25 can be centered in window 30 by adjusting the positionof unit 24 on the handle.

The preceding description demonstrates how the device of the inventionshows the golfer in advance the initial trajectory of the ball withinthe line of light 19 and quickly teaches the golfer proper club positionand position of the hands on the putter grip. In addition, the designsdescribed allow for optical units 11 and 28 to be positioned entirelybehind plane YZ of striking surface 8 so they do not interfere at anytime with the user's view of surface 8, ball 2 or index 9. A clubequipped with this device can be used for putting practice on anysurface, particularly on an artificial carpeted surface, therebyallowing a golfer to practice at home or at an indoor sports facility.

The scope of the present invention is not limited to the embodimentsdescribed above, but extends to any modification or variation obvious toone skilled in the art. In particular, it is possible to create a putterwhich completely integrates the device of the invention, specificallywith club 7 and shaft 5 or grip 6. In FIG. 2, for example, referencenumeral 32 indicates one possible location of the light beam transmitterand the electric battery inside the handle. Or a putter might bepre-equipped with a support to which the light device could be attached,allowing the club to be used for both practice and actual play, indoorsor out. Furthermore, the light beam may be supplied by various types oftransmitters so long as it can be collimated ,onto a plane and its coloris visible on the ground.

We claim:
 1. An auxiliary luminous device, for assisting a user withgolfing practice, comprising a light beam transmitter and an opticalunit arranged to diffuse a generated light beam in a plane;the devicebeing used in combination with a golf club having a striking surface;the transmitter and the optical unit being attached to the golf club;the optical unit being aligned relative to the golf club so that theplane in which the light beam is to be diffused extends perpendicular tothe striking surface of the golf club and passes through a point ofimpact between a golf ball, to be struck by the golf club, and thestriking surface, and the light beam, when diffused, forms a line oflight on the ground during a golfing stroke; and the optical unit beinglocated behind a plane defined by the striking surface.
 2. Thecombination according to claim 1 wherein the optical unit is attached tothe golf club remote from the striking surface.
 3. The combinationaccording to claim 1 wherein the light beam transmitter is a lasertransmitter emitting a parallel light beam.
 4. The combination accordingto claim 1 wherein the optical unit has a cylindrical lens for diffusingthe generated light beam.
 5. The combination according to claim 4wherein the optical unit comprises a reflector attached to thecylindrical lens and spaced from the transmitter.
 6. The combinationaccording to claim 5 wherein the transmitter is secured to the shaft ofthe golf club.
 7. The combination according to claim 5 wherein thetransmitter is incorporated within the golf club shaft.
 8. Thecombination according to claim 1 wherein the device further comprises anelectrical energy source to supply the light beam transmitter withelectrical power; andthe electrical energy source is attached to thegolf club.
 9. The combination according to claim 1 wherein the opticalunit and the transmitter are included in an electronic and optical unit;andthe electronic and optical unit is attached to an adjustable armreleasably mounted to a shaft of the golf club.
 10. A method of using anauxiliary luminous device, comprising a light beam transmitter and anoptical unit arranged to diffuse a generated light beam in a plane, toassist a user with golfing practice, the method comprising the stepsof:using the device in combination with a golf club having a strikingsurface; attaching the transmitter and the optical unit to the golfclub; aligning the optical unit relative to the golf club so that theplane in which the generated light beam is to be diffused extendsperpendicular to the striking surface of the golf club and forms a lineof light on the ground during a golfing stroke; and locating the opticalunit behind a plane defined by the striking surface so that the plane inwhich the generated light beam is diffused passes through a point ofimpact between a golf ball, to be struck by the golf club, and thestriking surface.